Whistle



FIG. 1 is a perspective view of a whistle showing my new design;

FIG. 2 is a front elevation view thereof:

FIG. 3 is a rear elevation view thereof:

FIG. 4 is a left side elevation view thereof:

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is bottom plan view thereof.

The ornamental design for a whistle, as shown and described.